23592-74-7Relevant academic research and scientific papers
Visible-light-driven Cadogan reaction
Qu, Zhonghua,Wang, Pu,Chen, Xing,Deng, Guo-Jun,Huang, Huawen
supporting information, p. 2582 - 2586 (2021/03/09)
Visible-light-driven photochemical Cadogan-type cyclization has been discovered. The organic D-A type photosensitizer 4CzIPN found to be an efficient mediator to transfer energy from photons to the transient intermediate that breaks the barriers of deoxygenation in Cadogan reaction and enables a mild metal-free access to carbazoles and related heterocycles. DFT calculation results indicate mildly endergonic formation of the intermediate complex of nitrobiarenes and PPh3, which corresponds with experimental findings regarding reaction temperature. The robust synthetic capacity of the photoredox Cadogan reaction systems has been demonstrated by the viable productivity of a broad range of carbazoles and related N-heterocycles with good tolerance of various functionalities.
Self-Assembled Multilayer Iron(0) Nanoparticle Catalyst for Ligand-Free Carbon-Carbon/Carbon-Nitrogen Bond-Forming Reactions
Akiyama, Toshiki,Arisawa, Mitsuhiro,Haneoka, Hitoshi,Harada, Kazuo,Hasegawa, Jun-Ya,Honma, Tetsuo,Mashima, Kazushi,Sato, Yoshihiro,Shimoda, Shuhei,Shio, Yasunori,Suzuki, Takeyuki,Tamenori, Yusuke,Tsurugi, Hayato,Tsuruta, Kazuki,Wada, Yuki,Yamada, Makito
, p. 7244 - 7249 (2020/10/12)
Self-assembled multilayer iron(0) nanoparticles (NPs, 6-10 nm), namely, sulfur-modified Au-supported Fe(0) [SAFe(0)], were developed for ligand-free one-pot carbon-carbon/carbon-nitrogen bond-forming reactions. SAFe(0) was successfully prepared using a well-established metal-nanoparticle catalyst preparative protocol by simultaneous in situ metal NP and nanospace organization (PSSO) with 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine (Si-DHP) as a strong reducing agent. SAFe(0) was easy to handle in air and could be recycled with a low iron-leaching rate in reaction cycles.
Bismuth(III) Triflate Catalyzed Three-Component Reactions of Indoles, Ketones, and α-Bromoacetaldehyde Acetals Enable Indole-to-Carbazole Transformation
Gu, Yanlong,Huang, Wenbo,Chen, Shaomin,Wang, Xin
supporting information, p. 4285 - 4289 (2018/07/29)
A three-component reaction of indoles, α-bromoacetaldehyde acetals, and ketones was developed by using bismuth(III) triflate as the catalyst to realize a straightforward approach for synthesizing carbazole derivatives. The reaction was established mechanistically through the autotandem catalysis of Bi(OTf)3 in the following two steps: (i) Friedel-Crafts-type alkylation of indole with α-bromoacetaldehyde acetal, which produced a tryptaldehyde-type intermediate and (ii) [4 + 2] annulation of this intermediate with the ketone component.
One-pot synthesis of carbazoles via tandem C-C cross-coupling and reductive amination
Goo, Deuk-Young,Woo, Sang Kook
supporting information, p. 122 - 130 (2015/12/30)
We have developed a highly efficient synthetic route to carbazoles that employs sequential C-C/C-N bond formation via Suzuki cross-coupling and Cadogan cyclization using commercially available or easily preparable starting materials. The developed method is compatible with electron neutral, rich or deficient substrates. The synthetic utility of this method was demonstrated by the concise syntheses of four natural products (glycozoline, glycozolicine, glycozolidine and clausenalene).
Amino-directed RhIII-catalyzed C-H activation leading to one-pot synthesis of N-H carbazoles
Jiang, Qibai,Duan-Mu, Dandan,Zhong, Wei,Chen, Hao,Yan, Hong
supporting information, p. 1903 - 1907 (2013/03/28)
One-pot synthesis: An efficient amino-directed one-pot synthesis of N-H carbazoles from unprotected 2-aminobiaryl compounds is reported. The free amino unit acts as both a directing group for ortho C-H activation and a functional group for construction of an N-heterocyclic ring (see scheme). Copyright
Mild and efficient nickel-catalyzed heck reactions with electron-rich olefins
Gogsig, Thomas M.,Kleimark, Jonatan,Nilsson Lill, Sten O.,Korsager, Signe,Lindhardt, Anders T.,Norrby, Per-Ola,Skrydstrup, Troels
supporting information; experimental part, p. 443 - 452 (2012/03/07)
A new efficient protocol for the nickel-catalyzed Heck reaction of aryl triflates with vinyl ethers is presented. Mild reaction conditions that equal those of the corresponding palladium-catalyzed Heck reaction are applied, representing a practical and more sustainable alternative to the conventional regioselective arylation of vinyl ethers. A catalytic system comprised of Ni(COD)2 and 1,1″-bis(diphenylphosphino)ferrocene (DPPF) in combination with the tertiary amine Cy2NMe proved effective in the olefination of a wide range of aryl triflates. Both electron-deficient and electron-rich arenes proved compatible, and the corresponding aryl methyl ketone could be secured after hydrolysis in yields approaching quantitative. Good functional group tolerance was observed matching the characteristics of the analogous Pd-catalyzed Heck reaction. The high levels of catalytic activity were explained by the intermediacy of a cationic nickel(II) complex potentially responsible for the successive β-hydride elimination and base promoted catalyst regeneration. Although these elementary reactions are normally considered challenging, DFT calculations suggested this pathway to be favorable under the applied reaction conditions.
Highly chemoselective Mono-Suzuki arylation reactions on all three dichlorobenzene isomers and applications development
Ullah, Ehsan,McNulty, James,Robertson, Al
, p. 2127 - 2131 (2012/06/01)
A Pd catalyst system is described that allows very high chemoselective monoarylation on all three isomers of dichlorobenzene. Direct application of these commodity chemicals to high-value ligands, anilines, azides, and carbazoles was achieved through this process discovery.
Dioxomolybdenum(VI)-catalyzed reductive cyclization of nitroaromatics. Synthesis of carbazoles and indoles
Sanz, Roberto,Escribano, Jaime,Pedrosa, Maria R.,Aguado, Rafael,Arnaiz, Francisco J.
, p. 713 - 718 (2008/02/09)
Reductive cyclization of nitrobiphenyls and nitrostyrenes to carbazoles and indoles, respectively, is carried out by triphenylphosphine under mild conditions catalyzed by a dichlorodioxomolybdenum(VI) complex. A one-pot procedure for the synthesis of regioselectively functionalized indoles has been developed from commercially available onitrobenzaldehydes and phosphoranes.
Triphenylphosphine-mediated reductive cyclization of 2-nitrobiphenyls: A practical and convenient synthesis of carbazoles
Freeman, Adam W.,Urvoy, Marie,Criswell, Megan E.
, p. 5014 - 5019 (2007/10/03)
The synthesis of a series of substituted carbazoles from the corresponding 2-nitrobiphenyl derivatives using a novel modification of the Cadogan reaction is described. Cyclization of the 2-nitrobiphenyls was achieved via reductive deoxygenation of the nitro groups using a slight excess of triphenylphosphine in a suitable solvent. We have observed a temperature dependence on the extent of conversion under these conditions, with higher boiling solvents affording higher yields across a range of substrates. The new reaction conditions are very straightforward and convenient to execute, tolerate a broad range of functional groups, and yield carbazole products in the absence of unwanted side products.
Microwave-enhanced cadogan cyclization: An easy access to the 2-substituted carbazoles and other fused heterocyclic systems
Appukkuttan, Prasad,Van Der Eycken, Erik,Dehaen, Wim
, p. 127 - 133 (2007/10/03)
A microwave-enhanced Suzuki-Miyaura cross-coupling reaction in combination with a microwave-assisted Cadogan reductive cyclization is presented as an easy access to a variety of 2-substituted carbazoles and other fused heterocyclic systems. Microwave irradiation was found very useful in minimizing the proto-deboronation issues in the cross-coupling reaction, and enhances the rate of reductive cyclization in a dramatic manner.
